Electric circuit breaker



April 18, 1950 J FLEWNG 2,504,513

ELECTRIC CIRCUIT BREAKER Filed Dec. 24. 1948- f'igl.

l v JIO 20 J5 13 15 E i I 30 29 l4 3 33., j 23 1 I I I 8 I 22 I Inventor William J. Fleming,

His ttorney.

Patented Apr. 18, 1950 ELECTRIC CIRCUIT WilliamJ.Fleming New to The 'rnmbuu'mee neeticnt llfltahucenn adgner his Mannlactnrlng Company, Plalnvllle, Coma, a corporation or con- Applleation December 24, 1348, Serial No. 07,103

5 Claims. (Cl. 200-118) My invention relates to electric switches or breakers oi the type shown in the Von Hoorn Patent 2,150,013.

One object is to provide means for ensuring adequate pressure between the contacts.

Another object is to simplify the construction of such a switch.

Another object is to provide means forv 7 quick and effective opening 01' the circuit.

Another object is to provide a switch or breaker in which the opening force varies in proportion to the variation in contact pressure.

The accompanying drawings andthe following specification and claims will set forth one form of my invention.

Fig. 1 is a longitudinal sectional view showing in full lines the position of the parts when tripped automatically.

Fig. 2 is a similar view with the parts in the closed circuit position in full lines and in the reset position in dotted lines.

Fig. 3 is a cross-sectional view taken on the plane of the line 3-3 of Fig. 2.

The mechanism is shown mounted in a housing consisting of a base or body portion 1 and a cover 8. The circuit terminals 9 and III are mounted at opposite ends of the body. The switch contacts H and I! are mounted in the body, contact 12 being carried by a movable arm [3 and contact I I being flexibly mounted for instance on a flexible strip ll connected to terminal ill.

The arm I3 is electro-conductive and has a hinge pin l5 guided in slots IS in opposite sides of the body. This arm carries the contact i2 at one end and has a tip H at the other end normally supported by a shoulder It in the bimetal current actuated strip is which is supported by a bracket 20 connected to terminal 9 and adjustable by a screw M which is supported by a member 22.

The lower end of strip is is connected by a flexible conductor 23 to the adjacent end of the switch arm i3 so that when the switch arm is in the closed circuit position 01 Fig. 2 current can flow from 9 to 20, 19,23, ll, 12, ii and II to II.

The manual operator 24. is pivoted at 25 and has shoulders 26 and 21 to engage the upper surface of arm I3. Operator 24 has a yoke 28 connected to swing with it and its lower end engages beneath arm [3 at 29 in the position of Fig. 2 at 30 in the full line position of Fig. 1 and at 31 when in the dotted position of Fig. 2.

A spring 33 is interposed under compression between arm l3 and the left end of two-armed 2 tilting lever or rocker 33 which is pivoted at 33 in slot 33 in the base.

In the position of Fig. 2, the spring 83 presses the right hand end of the switch am It upward against the lower end 01 operator 24 and biases the left end of arm l3 downwardly against the catch shoulder il oi the bimetal strip. At the same time, the spring is biasing lever 34 anticlockwise so that its right hand end presses upwardly beneath the movable contact II.

In case of an overload suflicient to warp strip is away from the tip ll of arm l3, the arm will be suddenly tripped to the position of Fig. 1 under the impulse of spring 33 which will tilt the operator 24 to the position of Fig. 1 where the lower end of extension 28 will turn into the notch 3|.

when the bimetal has cooled suiiiciently the switch arm may be reset to the position of dotted lines in Fig. 2 by turning the operator 24 so that the extension 28 will raise the left hand end of the arm into latching position. The circuit can then be closed by turning the operator back to the position of Fig. 2 during which movement the shoulder 25 of the operator will press downwardly on the switch arm and tilt the arm against the spring 33. As the spring is compressed it tilts lever 33 and raises contact ii until the contact I! engages and presses it downward by the force applied to arm i3 by operator 24. In this position, the spring presses the lever 34 upwardly against strip H and thus applies pressure of contact ll against II. In this way the single spring 33 serves to pressthe contacts together in closed circuit position and also biases the main switch arm to the open circuit position when it is released by the bimetal latch or when the operator 24 is turned to the OFF position.

As the flexibly mounted contact in eflect tilts or rotates about one edge during opening oi the circuit there is a prying action. The more you increase contact pressure, the more you increase the force tending to move the contact I! to the open position.

I claim:

1. In a circuit breaker, a switch arm, a current-actuated latch for supporting one portion of said arm, a movable contact for supporting a remote portion of said arm, apivoted operator for engaging an intermediate portion oi said arm and pressing said arm against said latch and against said contact in a closed circuit condition and a spring-actuated pivoted rocker pressed by the action of said operator and by said switch arm and pressing said contact against said am.

2. In a. circuit breaker, a tilting switch arm, a

current-actuated latch ior supporting one portion of said arm. a movable contact for supporting a remote portion of said arm, a pivoted operator Mating an intermediate portion of said arm and pressing said arm against said latch and against said contact in a closed-circuit condition, a pivoted rocker having two arms and a spring interposed between one oi said rocker arms and said switch arm, the other rocker arm pressing said contact against said switch arm.

3. In a circuit breaker, a switch arm, a current-actuated latch for supporting one portion 0! said arm, a movable contact for supporting a remote portion of said arm, a pivoted operator for engaging an intermediate portion oi said arm and said arm against said latch and against said contact in a closed-circuit condition and means including a pivoted rocker having two arms and a spring interposed between one of said rocker arms and said switch arm, the other rocker arm pressing said contact against said switch arm.

4. A circuit breaker including an insulating base. a contact movably supported in the base, a

4 a manually actuated operator ior pressing said switch arm into latching engagement with said movable switch arm having a contact at one end 5 for coacting with said movably supported contact, a current-actuated latch coacting with the other end oi said am, a spring supporting said arm,

current-actuated latch and into circuit-closing engagement between said contacts and a member pivoted in the base and biased by said spring to press said movahly supported contact toward the contact oi the switch arm.

5. In a circuit breaker, a base, a floating switch arm, a pivoted support for said arm in said base, a current-actuated latch coacting with said arm, a contact movably mounted in the base, an operating member for pressing said arm against said latch and said contact, a spring for retracting said switch arm upon an overload in the circuit and a rocker pivoted in the base and interposed between said spring and said contact for pressing said contact against said switch arm.

WILLIAM J. FLEMING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,150,013 Von Hoorn Mar. 7, 1939 2,820,355 Frank et a1 June 1, 1943 2,418,359 Link Apr. 1, 1947 

